


Not the End I Wanted

by mirror_cannibal



Category: Kuroshitsuji | Black Butler, Supernatural
Genre: Crossover, I'm not quite sure how to tag this so I'll just add stuff as I go, Multi
Language: English
Status: Completed
Published: 2016-11-25
Updated: 2016-11-25
Packaged: 2018-09-01 19:07:26
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,184
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8634481
Author URL: https://archiveofourown.org/users/mirror_cannibal/pseuds/mirror_cannibal
Summary: "Why would Crowley want to trap me?""He's angry with your contract, Sebastian. You know how much he stresses the usual terms. And this—well, this is far from the usual terms.""It was not under usual terms in which we made this contract, Castiel.""You cause a lot of trouble with your little rewritten contracts in the future, so I'm here to put a stop to it before it starts." Ciel Phantomhive made a contract with the demon Sebastian under strange circumstances...how does Sebstian's real boss, Crowley, feel about this? What problems does this rewritten contract cause in the future, and to what extent will Castiel and the Winchesters go to prevent that?





	

**Author's Note:**

  * For [unspoken_code](https://archiveofourown.org/users/unspoken_code/gifts).



> whoop whoop, first crossover fic on this account!!

"A letter for you, young master." Sebastian spoke in his usual melodic voice, standing before Ciel's desk with a white envelope in his hands. Behind the desk, the head of the Phantomhive Manor sat, tapping his fingers against the wood with a bored expression in his blue eye. When the butler spoke, the young boy scoffed and turned to look out the big window behind the desk.

"Read it then, if you will." The boy spoke almost sarcastically, a teasing undertone grating against the syllables as they left his throat. 

Unperturbed, the butler smiled pleasantly as he cracked the seal open. "Yes, young master." He removed a plain white letter, clearing his throat softly before beginning to read: "To the Head of Phantomhive Manor...The queen of England..." his voice trailed off. Ciel immediately turned back to look at the butler, a question clear in his eye. Sebastian lowered the note onto the table. "The queen of England, young master...it appears she is dead. And her guards want you to find her assassin."

Ciel wrinkled his brow. "Her guards?" he questioned. "Her _guards_ want _me_ to find her assassin? After they apparently couldn't protect her in the first place?"

"You are the queen's guard dog, young master. Perhaps they can't do as good a job as you ever did." Sebastian couldn't stop the smile from flitting across his face.

"Oh, shut up," Ciel stood up. _How on earth did those idiots manage to fail so miserably at their own jobs? And now they can't even fix it themselves? Honestly._ "We're going into London to investigate. What time will our guests arrive?"

Sebastian snapped open his silver pocket watch. "Just ten minutes, my lord."

Ciel sighed loudly, tapping his finger against the desk. "Tell the servants to entertain them for the night. We most likely won't be coming back for a few days...this is serious."

"Of course, young master." In a flash, the trusty butler was gone.

Ciel let out another frustrated breath, dragging the letter across the desktop to read the elegant writing himself. _So the queen really has been murdered..._ He frowned. _How could they let that happen?_

Suddenly a rough, unfamiliar voice spoke from behind Ciel. "Are you Ciel Phantomhive?" His heart in his throat, Ciel couldn't help the way his body started as he spun around to locate the speaker. His eye landed on a man that he had never seen before, whose body was draped in a simple beige trench coat. Ciel's wild gaze quickly flitted over the man's dark hair and blue eyes, eerily similar to Ciel's own features. 

"Who are you?" Ciel gasped out as soon as he had the breath to. "How did you get in here?" The man was standing before the big window, directly in between the wall and Ciel's desk. _How the hell did he get in here?_

"I am Castiel," the strange man said, his voice expressionless. "But you…you are only a child. You can't be the Ciel Phantomhive I'm looking for." His last sentence almost seemed more of a question than a statement, and Ciel realized he was shivering under the force of the man's electric blue glare.

"Sebastian!" Ciel automatically called, backing away from the man, Castiel. _Where is Sebastian, why isn't he here..._

"I would advise you not to do that." Castiel stepped forward, and Ciel noticed a silver blade in his hand, previously hidden by the shadow of his coat. A million questions swirled in Ciel's mind, but fear rose above them all when he saw that blade. _What does he want from me?_

It was then that Sebastian entered the room, his eyes going wide as they landed on Castiel. "You?" he immediately said, shock in his voice. "What are you doing here?"

"You know this man?!" Ciel demanded, his heart racing. "Who is he? Why is he here?"

"Calm yourself, my lord, he is not someone you should fear. He did not come for you; if he did you'd already be dead." Sebastian said softly as Castiel began walking towards the butler. _Didn't come for me?_ Ciel found himself thinking, _Then why the hell was he asking me if I was Ciel Phantomhive?_

"I know what you are, butler," Castiel spoke in his ominously low voice, holding the blade in a ready position, "and I should advise you I did not come alone. This will not end like last time."

Sebastian laughed, and Ciel began to slowly move to the side, so that he wasn't sandwiched in between the two when the fighting started. "Oh?" the butler grinned, "Well, I should hope not, that ending was horribly boring. Now, if you'll excuse us, we have some business to attend to. You see, the queen has just been murdered."

"Your queen is fine," Castiel said, "Crowley's setting a trap for you. I wanted to get to you first. I brought friends this time."

"Why would Crowley want to trap me? And you don't have friends, Castiel." Sebastian moved slowly towards Ciel as he spoke, which worried the boy even more. He had never seen his butler so uneasy around a man; and as far as he could tell, this Castiel was no demon or reaper. _So what is he? And why does he intimidate Sebastian so much?_

Castiel moved closer to Sebastian, smoothly positioning himself between the demon and the boy before either one could make another move. "He's angry with your contract, Sebastian. You know how much he stresses the usual terms. And this—well, this is far from the usual terms."

"It was not under usual terms in which we made this contract, Castiel. The contract is fine; the boy knows all the terms and has agreed to them."

Ciel spoke up, feeling brave enough to intervene now that his own name had come up. "It's true; I have. Why don't you tell me just who you are and how you got into my house, Castiel?"

Cas turned to look at the boy. "I am an angel of the Lord, Phantomhive. I can smite you as easily as this demon here, who won't live long enough to worry about what Crowley would do to him."

"Who's Crowley?" Ciel was aware that the frustration at his own lack of information was beginning to show in his words, but all he wanted was straight answers.

"Crowley…he's the king of hell. And he's your butler's real boss." Castiel turned back to Sebastian, dismissing Ciel with a quick turn of the head. "Now, you cause a lot of trouble with your little rewritten contracts in the future, so I'm here to put a stop to it before it starts."

Ciel was rolling his eyes in exasperation when he noticed two shadows on either side of the doorway behind Sebastian. The second his mind realized what they were, he called out, "Sebastian!" but it was too late. One of the shadow swung into the room, and a glimmer of water was thrown from a container in its hand. For a moment everything seemed to slow down, until Ciel could see the arc of water hanging in the air. But before he knew it, time had sped up again and then his beloved butler was kneeling, gasping in shock as the water burned his skin.

Before Ciel could comprehend what was happening, the so-called angel was stepping forward, swinging his silver blade into Sebastian's chest. Sebastian's wide eyes locked with Ciel's gaze over Castiel's shoulder, shocked failure on the butler's face. "S-Sebastian?!" Ciel rushed forward, but the second shadow had come up behind the boy while he was distracted. Before he could take more than a few steps, Ciel felt a strong pair of arms wrap around his shoulders, holding him back from the impaled demon.

"No, no," Ciel found himself moaning, over and over again, "no, no, no, no..." He struggled against the hold, but the man didn't budge. "Sebastian!" Ciel yelled, his voice hoarse with emotion he didn't know he had, "Sebastian!" Even as he screamed, the disbelief was rushing through his head. _He's not really dying, he's faking it, he's done it before, he can't be dead…he's all I've got left…_

But somehow he knew this time was different. Castiel ripped the blade from the demon's chest and Sebastian fell to the ground, his body limp. Ciel fell to his knees when the man finally let him go. He barely felt the impact of the hard floor against his legs, automatically beginning to crawl to the dying butler. "Sebas-stian…" Ciel's voice was uneven and wavering, and the angel stepped away, towards the two other men, as Ciel got closer to the demon. "You…you're gonna be ok, aren't you? You're not going to leave me?"

As Ciel came up to the demon's head, he noticed the absence of light in the red eyes. Sebastian opened his mouth slightly, trying to speak, but crimson blood was all that bubbled up. It slid down his pale cheek slowly, moving thickly and lethargically in that strange way that only blood can move. "Young master…" Sebastian forced out, his voice weak. "Even I can't survive that. I…I'm sorry. I couldn't…fulfill…the contract." He broke off his words as more crimson liquid escaped his lips.

"Sebastian?" Ciel could hear the terror in his own voice. The butler's body was still suddenly, his red eyes dim and his chest unmoving. "No…you can't leave me…you promised you wouldn't leave me! Don't leave me alone!"

 _He's really...gone?_ Ciel didn't recognize the sting of pain in his eyes until he felt the wetness of tears against his cheeks. Within seconds, his body was wracked with sobs. Each breath was a struggle, as the squeezing pain in his chest didn't seem to want Ciel to breathe at all. _He couldn't die...He never died...Until now...Until him._ Ciel glared at the angel, Castiel, through his tears. Overcome with a strangely unfamiliar wave of emotion, Ciel screamed, "You took him from me! He was all I had and you took him!" Surprised by his own vehemence, Ciel staggered to his feet.

 _I can't kill him. He's an angel. He killed Sebastian. I can't kill him. I have to go._ His mind seemed to be moving slower than usual, and his head felt like it was stuffed with cotton. Ciel moved his feet, one at a time, slowly, as the tears swam across his vision. _The door. Get to the door, then run. Down the hall, down the stairs, find Mey-Rin, or Baldroy, or even Finnian...someone._ The angel stepped forward, blocking Ciel's path, while the other two men looked on with puzzled expressions.

"Cas, what's this kid's deal?" the shorter of the two asked softly, "Didn't we just save him from a contract?"

"Sebastian was a freelancer, if you will," Castiel quietly answered, and Ciel listened, pausing his marionette-like walk, without really hearing the words. "He negotiated his contracts differently. It's possible he never fulfilled this boy's contract. He never got Phantomhive's soul, and the boy never got whatever he was promised."

Castiel approached Ciel, who couldn't muster the energy to move around the angel to escape. "What were you promised, Phantomhive?" Castiel demanded, a fire in his blue eyes.

Ciel looked up at him. "It doesn't matter now," he whispered, surprised he was able to get the words out. "He's gone. I'll never get it."

"What were you promised?" The angel repeated.

"What was I promised?" Ciel softly parroted, his voice almost a whisper. The angel took another step forward. _He's too close,_ Ciel found himself thinking, even though the man was still a meter or so away. _He's too close. He needs to back up. He needs to leave. He needs to die._

"What were you promised?" Castiel's voice had an edge of impatience in it; an edge that reminded Ciel of his own voice whenever he got exasperated or frustrated. Ciel's gaze swung around the room. He blinked tears out of his eyes, and his sharpened vision landed on the wide window at the back of the study. His path to it was clear. He just needed to be fast.

There was a tune stuck in his head, that he'd heard long ago, on one of those cases that had stuck with him and plagued his nightmares for days to come. There was a memory of a man, with orange hair and a music box in his hand. _London bridge is falling down,_ the man sang, over and over, _falling down, falling down..._ Ciel's eyes locked on the window. His legs were moving before he'd even told them to. _Phantomhive is falling down,_ Ciel sang in his head, _falling down, falling down..._ There were a few shocked yells from the men behind him, but Ciel didn't stop, running full force into the glass that stretched across the wall. It shattered easily, almost too easily, and Ciel felt a million pinpricks of pain as tiny bits of glass attacked his skin. _Phantomhive is falling down...goodbye, Sebastian._

**Author's Note:**

> I'm rewriting each chapter from this old fic I already had, so I'm not sure how often I'll be updating...
> 
> Also the POV will be different with each chapter, so don't worry about the lack of Supernatural characters for now ^_^


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